The invention relates to an apparatus and to a method for treating a surface, in particular for spraying an insulating foam, for example polyurethane foam, on a wall. Examples of spraying apparatus may be seen in British patent No. 1,300,352, and in U.S. Pat. Nos. 3,460,177 and 3,783,819.
The invention relates to an apparatus of the above kind, which are particularly suitable for treating the inner surfaces of the walls of a tank of prismatic or of cylindrical shape, such as for example a tank for transporting or storing liquefied gases (natural gas, methane, propane). Tanks of this kind, in particular, for seagoing tankers, are described for example in applicant's British patent No. 1,173,424.
In this connection it is remarked that the expression "treating a surface" covers a number of different operations, such as spraying an insulating foam, for example polyurethane foam, on a surface, spraying paint on a surface, cleaning a surface, sandblasting or grinding a surface, or even rolling a surface.